Spatial Light Modulators
HOLOEYE´s Spatial Light Modulator (SLM) systems are based on translucent or reflective liquid crystal microdisplays. These devices can modulate light spatially in amplitude or phase, so they act as a dynamic optical element. The optical function or information to be displayed can be taken directly from the optic design software or an image source and can be transferred by a computer interface.
Implementation is accomplished using the HDMI port of a standard PC graphics card. The SLM can be used just like an external plug & play monitor.

SLM Software Features
All HOLOEYE Spatial Light Modulators can be controlled by a Configuration Manager (Windows). This software gives the opportunity to control all relevant image parameters and provides an easy gamma control to configure the device for different applications and wavelengths.

Aditionally an SLM Pattern Generator Software is delivered with the SLM. Key features are:
- computation of computer generated holograms (CGH) from user defined images
- generation of SLM signals representing basic optical functions such as lenses, gratings, axicon and vortex functions
- superposition of CGH's with basic optical functions to combine functionalities

For easy display of images and image sequences on the Spatial Light Modulator an SLM Slideshow Player software is also delivered with the kit.
Besides that an SLM Display Software Development Kit (SDK) is availalbe which provides APIs (Application Programming Interface) for National Instruments™ LabVIEW, MathWorks® MATLAB®, Octave and Python™ environments.

The PLUTO-2 phase modulator models are based on reflective LCOS microdisplays with 1920 x 1080 pixel resolution and 8.0 μm pixel pitch.

The PLUTO-2 series covers different versions optimized for different applications and wavelength ranges from 350nm up to 1700 nm. Furthermore high retardation display panels are available (VIS and NIR) which enable a modulo 4 π or 6 π encoding of optical functions depending on the wavelength.

The pulse code modulation for digitally addressed devices leads to a slight superimposed phase flicker. For some applications a stable phase response is required. This can be accomplished driving the high retardation display versions with low voltage settings for 2π phase retardation, however compromising the response time.

All different phase display versions can be driven with the same PLUTO-2 driver units. This provides you the flexibility to ubgrade / adapat the SLM device to another version for different applications without the need to purchase a complete new SLM kit.

The PLUTO-2 driver also features a dual-core ARM® Cortex™-A9 processor which includes on-chip memory. This enables the user to program additional functionality which is directly processed on the PLUTO-2 device. The dual-core system runs an embedded Linux™ SMP operating system and includes a library which provides full control and supervision of the display and driver board.

Some PLUTO-2 SLM display versions are equipped with a dielectric mirror coating to increase the reflectivity. Due to the increased reflectivity less absorption occurs and these display versions can be used with higher incident laser power compared to the standard versions.